Pore space analysis and estimation of transport properties of deteriorated cementitious material using synchrotron microtomography

Authors: M.A.B. Promentilla, T. Sugiyama, T. Hitomi, N. Takeda
Paper category: conference
Book title: Concrete Durability and Service Life Planning – ConcreteLife’09
Editor(s): K. Kovler
Print ISBN: 978-2-35158-074-5
e-ISBN: 978-2-35158-085-1
Publisher: RILEM Publications SARL
Publication year: 2009
Pages: 498 – 506
Total Pages: 9
Language: English

Abstract: For concrete structures that are being used in nuclear waste repository, the long-term durability performance of such cementitious materials when in contact with water could be at risk due to leaching of Ca2+. Since the dissolution and decalcification of cement paste hydrates modify the microstructure, and thereby the transport properties, it is necessary to evaluate the pore structure-transport properties of deteriorated cementitious materials to predict and control the service life of concretes in such post-construction use. This paper presents the method for image acquisition and image analysis to visualize and quantitatively characterize the 3D micro-geometry of pore space in deteriorated cementitious materials with the aid of synchrotron microtomography. The specimen for X-ray imaging was taken from a mortar that was subjected to an electrochemical migration test to accelerate the dissolution of cement paste hydrates. From these microtomographic images (voxel resolution of 0.5 µm), 3D random walk simulation was employed to measure the diffusion tortuosity, which is the pore structure-transport parameter associated to the percolating pore space. Using the 3D (skeletonization) medial axis algorithm, geometric properties such as the path tortuosity, pore body volume, throat surface area, and pore coordination number are also computed from the pore-throat network representation of this percolating pore space.

Online publication: 2012-05-16
Publication Type: full_text
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